Machine for inserting lag-screws.



M. ROTHFUSS.

MACHINE FOR INSERTING LAG SCREWS.

APPLICATION FILED Aue.21.1.913.

1,149,222. Patented Aug. 10,1915.

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COLUMBIA PLANDGRAPH CO" WASHINGTON, D. C.

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livracnr vn FOR insnntrrne nac scnnws.

To all whom z'zf'may concern:

Be it known that LlVlIoIIAnL Rotr rruss, a citizen of the United States, residing in the city of Williamsport, in the county of v Lycoming and State of Pennsylvania, have invented a new and usefulMachine for Inserting Lag-Screws Used in Assembling Certain Articlesof Furniture,

j The lag screws referred toarebolts ha aing at one end a wood screw thread, and at the other end an ordinary screw thread to carry a nut, the same being employed to'join different together. 7 I

My invention relatesto improvements in machines to insert these screws where required, and is designed to automatically grip the screw, revolve it until it is driven to the proper depth, and then automatically stop the. revolution and release the screw; whereby I obtain greater rapidity of operation and also more exactness in the depth to which the screw is driven, than can be attained by any other device now in use.

The accompanying drawings illustrate my machine, in which- Figure l is a perspective side view of the attached to the wall or post machine, Fig. 2 is a detail view of the upright A shaped iece f and its arm m.

The fi 'ame of the machine consists of a bracket 0:, or any suitable table, carrying a shaft 8 in two bearings t t, having a driving pulley (Z, and the front end fitted with a chuck a for gripping the lag screw. In one or both of the bearings 23 t are suitable devices, not shown, to prevent longitudinal motion of the shaft.

The driving pulley (Z has a limited lateral motion on the shaft and normally runs loose. To the inner arms of the chuck is attached a friction sleeve k to engage a corresponding friction surface or cone on the outer hub of the pulley (Z, so as tocause the shaft to revolve when the two friction surfaces are brought into contact. Upon the shaft adjoining the inner hub of the pulley (Z, is a loose collar 9. This collar, which does not turn with the shaft,has a finger y t which extends laterally somewhat over the inner hub of the pulley, and turns downward into an annular groove .9 in the. pulley hub. To the undersideof'the collar is rigidly attached an Specification of Letters Patent.

portions of an. article of furniture perfect uniformity and;v

arm a which extends back underneath the frame of the machine. In this arm 2' is an opening Z into which the end of the upright arm of the lever Z is inserted. The lever Z is pivotedat its elbow on a piece projecting downward from the frame of the machine. A treadle it carries an upright rod 9 which is hinged at its lower end on the treadle, and the upper end of which rod contains a notch 42 which engages a pin on the horizontal arm of the lever Z. An upright A shaped piece f, which I is hingedat both feet to the floor, so as to allow a forward and backward motion of its upper end, extends upward beneath the ma chine and carries an arm which extends underneath and forward to the front of the chuck,vwhere it forms a stop 6 for the piece of furniture operated upon. The said arm m is pierced with a hole 8 through which passes the rod g connected with the treadle, so that when the arm m is moved backward or forward it carries with it the upper end and thereby release the friction gearoof the pulley.

A spiral spring a in the chuck, when released, opens the jaws of the chuck, and a spiral spring 0 extending from a suitable point in the rod 9 to the arm m serves to raise the treadle. when the foot of the operator is removed.

It is apparent that the motion and running loose, and a lag screw being inserted in the jaws of the chuck, if now the treadle is depressed by the op erator, it will follow that by means of the rod 5/ and pivoted lever Z, the arm 71 together with the collar q and pulley cZ will be thrust forward until the friction cone of the pulley comes into contact with the friction surface attached to the chuck and shaft, causing the shaft to rotate, and at the same time the inner arms of the chuck will be expanded causing the jaws a to grip the lag screw and revolve it until it is inserted to the depth required. As the lag screw is being inserted, the piece of furniture being operated on ismoved forwarduntil it strikes the stop 6, which forces backward the arm pulley being in g m and pushes the notch in the rod 9 off the pin inthe lever Z, whereupon the spring 3) 7 Patented Aug. 1c, 1915. V Application filedwAugust 21, 1913. Serial No. 785,896.

instantly,- through the means indicated, Withdraws the pulley cl from the friction driving surface, so that the shaft stops rotating and the? spiral spring at open'sithe jaws of the chuck and releasesthelag screwJ The operator then raises his foot from the treadle andthexspring 0 raises the treadle and with it the rod 9 into position to again engage the pin on the lever Z, and the weight n 1 1 In a machinefor inserting lag screws the combination with arotatable" shaft and a gripping chuck thereon, a member slidv able on theashaft' and operati e'ly' connected to said chuck, means co-acting'I with the member normall y 'to hold 'the chuck in iiioperative position, and. means adapted to engage said member to cause the chuck to engage andho'ld a screw.

Thecom'bihation with a rotatable shaft and a chuck having pivoted arms with gripping jaws, asleeve slidable on the shaft and" a spring between the sleeve andchuck, pivoted links connecting the arms and sleeve, a= shiftable driving pulley on the shaft adapted to operativeliy" engagesaid sleevetoclose the gripping jaws, and means adaptedi to shift said pulley.

3. The combination with a rotating shaft and its supportingframe and a gripping chuck on the shaft, of a shiftable pulley on theshaft having an annnlarly, grooved hub v ca letor this atent ma 'te'ottameat m V a gripping chuck thereon;

two subscribing having a collar embracing the" shaftland a said chuck and sleeve, a-

finger on-the-collar engaging the grooved.

hub, and treadle meehanisln for actuating the slidable arm.

5. In a machine for inserting lag screws,

the conabinatio'n with a rotatable shaft and of' a member slid able on the shaft and operatively connected to said chuck, means meeting-with the member normally to hold the chuck in inoperative position, means adapted to engagesai membento cause the chuck to engageand p hold a screw, and a; movablestop devicein front of the chuck, operable when pressedback by a piece of furniture, to automatis call y-c release the gripping chuck.

In testimony'whereof I have signed my name; to this specification; in: the presence of witnesses: I

ROTHFUSS, f

, Witnesses: r c

E. SWINE ART, OnIvnIrJ'. DECKER;

five cents each, by ar lliressin'g the Commissioner. ot'Baten-ts, Washington,iD..G.i v 

